[Marty Ward]

I was thinking you could limit what you could steal and research. Maybe grouping the techs, say if you capture shard I you could research to shard IV.
I was thinking that the intermediate tech would be a requirement of each level, or group of levels, in addition to whatever else is already required. Since the AI is going research the intermediate level anyway it shouldn't matter if every level needs it, it only needs to be researched one time. You wouldn't change the research files you would change the tech file.